Field of the Invention
The present matter relates to a method of preparing and cooking cheese, specifically natural cheese of the pasta filata type, by ohmic heat treatment.
Background
Natural cheese, particularly of the pasta filata family (including but not limited to mozzarella, provolone, or blends thereof) are typically prepared by cooking and processing under high temperatures. Traditionally, the process involves introduction of enzyme additives to warm milk content, activating the catalyzing affect of enzymes and facilitating protein bonds. As nascent fibers form, semi-solid curds can be separated from the liquid whey. It is usually at this point that the early stage of processing is initiated wherein temperatures are increased and initial churning causes nascent pasta filata fibers to bond, stretch and form.
The conventional manufacturing method for heating and forming the nascent cheese mass at this stage is by way of submerging the cheese curds in a hot water bath and initiating initial churning and stretching by auger. The hot water bath provides heat to the immersed body of curd. The heat from the hot water bath penetrates the curd while it is initially churned and stretched to form the nascent cheese mass. Passive heating by this method results in a warmer external cross sectional layer and a cooler internal layer of the nascent cheese mass once it is formed. To reach the proper internal temperature during this cooking process, a higher than desired water temperature and longer than desired immersion time is required. This results in uneven cross-sectional heating of the nascent cheese mass. The higher temperature and long exposure time results in a greater amount of denatured enzymes and bacteria at the outer layer as well as butterfat loss.
At a smaller scale, particularly for artisanal hand crafting, unseasoned hot water is used to churn and stretch the curd. Salt may be separately added prior or subsequent to nascent cheese formation. Large scale manufacturing is tailored to mimic this traditional process wherein curd is churned and stretched in hot liquid bath. Seasoning typically occurs while the nascent cheese mass is being formed by exposure to brining liquid. Exposure time to brine solution becomes a limiting factor given extensive reliance on brine to heat and cool the cheese. The range of achievable flavor profile is more limited at the large scale manufacturing level since there is little opportunity to control seasoning. Other disadvantages of the brine immersion process include substantial loss of fat content and flavor. Other drawbacks include large amounts of pollution and toxins disposed from volumes of used brine liquid. Energy is required to continually heat large volume of brine. The amount of space required to accommodate the volume of brine involved for large scale manufacturing takes up substantial floor space.
Alternative manufacturing methods have been devised to minimize reliance on liquid brine for heating and cooling. More popular alternatives rely on steam to heat the nascent cheese mass. See WO 1999053749. Although speed is improved as a higher temperature is achievable by steam, the quality of the cheese is compromised by overheating. Other less conventional methods of heating without liquid brine have included ohmic (electric) heating. The common application have been primarily for pasteurization or sterilization purposes wherein food is exposed to high heat levels towards the end of a process. However, given the high temperature requirement within industries where ohmic heating is applied, the types of food cooked have been primarily egg products where texture and flavor is least compromised by the high temperature. As it has been applied to cheese production, this method has been used only to sterilize soft unripened cheese near the end of the cheese making process. See US 20110045133.
There remains a need for a method and device to heat and produce nascent pasta filata cheese in an efficient and improved manner for large scale manufacture. The goal of such an invention would be to improve on flavor, lower energy expenditure, eliminate use of liquid brine, and reduce spatial foot print of manufacturing equipment. No such solution exists to date that addresses each and every of these concerns effectively.